The present invention relates to electric machines and, more particularly, to electric machines having a housing which is used to cool the electric machine.
Electric machines include a stator and a rotor which rotates relative to the stator. Electric machines may operate as a motor, a generator or a motor/generator capable of selectively operating as either a motor or a generator. When operating as a motor, electrical current is input into the electric machine to generate a mechanical torque. When operating as a generator, mechanical torque is input into the electric machine to generate electrical current.
In some applications, electric machines require the use of a cooling system to remove heat from the electric machine during operation. The stator windings are often responsible for generating the majority of the heat during operation of the electric machine. As a result, it is generally desirable to cool the stator either by directly removing heat from the stator windings or by removing heat from the stator core. One common method of removing heat from the stator core is to mount the stator in a housing commonly referred to as a “water jacket” wherein the housing and the stator core are directly engaged and the housing includes a plurality of liquid coolant passages. A coolant, such as water, is circulated through the housing passages to remove heat from the housing. The housing thereby removes heat from the stator core and, consequently, the stator windings.
Improvements in the housing structure of such electric machines and the cost efficient manufacture of such housing structures remains desirable.